July 19, 2010

Two University of Nebraska researchers, Adam J. Liska and Richard K. Perrin, have published a new study in Environment Magazine that measures the GHG emissions associated with military operations necessary to protect international oil trade.

In order to have a balanced assessment of the climate change impacts of substituting biofuels for gasoline, a comparison of all direct and indirect emissions from both types of fuel is required. The analysis presented here contributes to a more complete assessment of total GHG emissions related to gasoline use, by including emissions from military activities related to the protection and acquisition of foreign crude oil.

According to their numbers the GHG emissions associated with military operations is quite large.

The elimination of Middle East oil imports would allow cessation of military oil security activity, equivalent to a 20-percent reduction in conventional U.S. military activity and emissions, which in turn is equivalent to 17.5 g CO2e per MJ of gasoline energy now imported from the Middle East

That is, according to the authors, roughly equivalent to the 14 to 27 g CO2e per MJ currently attributed to corn ethanol energy due to consequential indirect land use change.

It is an interesting study. Not only are there substantial emissions associated with the military operations necessary to secure foreign oil, but there are also large monetary costs.

Several studies have estimated the fraction of military expenditures attributable to securing oil supplies, from which we may be able to infer the fraction of GHG emissions. These estimates suggest that $27 to $138 billion dollars is spent annually by the U.S. military for protection of Middle Eastern maritime oil transit routes and oil infrastructure, with an average of $84 billion dollars per year.

The authors note that there is considerable uncertainty in modeling the indirect emissions for petroleum just as there is in indirect land use assessments for corn ethanol. I am sure that this is just the beginning of a much larger debate on the true emissions of petroleum. But it is an important debate to have if we are going to require that biofuels meet certain emissions reductions compared to petroleum fuels.